This invention relates generally to the monitoring of subsurface geologic formations of interest, and more particularly to ballistic deployment of a projectile data sensing apparatus into a subsurface geologic formation of interest to enable such monitoring.
Wells are drilled to recover naturally occurring deposits of hydrocarbons and other materials trapped in subsurface geological formations in the earth""s crust. A slender well is drilled into the ground and directed from a drilling rig on the surface of the earth or a body of water (e.g., an ocean) to a targeted subsurface location. In conventional xe2x80x9crotary drillingxe2x80x9d operations, the drilling rig rotates a drill string comprised of tubular joints of steel drill pipe connected together to form a drill string. The drill string is used to turn a bottom hole assembly (BHA) and a drill bit that is connected to the lower end of the drill string. During drilling operations, a drilling fluid, commonly referred to as drilling mud, is pumped and circulated down the interior of the drill string, through the BHA, downhole tools and the drill bit. Drilling mud flows back to the surface in the annulus between the drill string and the cased or uncased wellbore.
During the drilling phase the weight of the drilling mud is closely managed to ensure safety of the drilling rig and quality of the well. The drilling mud density is frequently adjusted using weighting agents designed to maintain the density of the drilling mud within a certain favorable range. The favorable range of mud density during drilling depends, at least in part, on the pressure of the fluids in the pores of the formation. The mud density should be sufficient to hydrostatically balance the formation pressure in order to stabilize the well and prevent unwanted entry of formation fluids into the wellbore. However, excessive mud density causes drilling mud or wellbore fluids to enter the formations possibly damaging the formation and causing well control problems due to loss of fluid from the wellbore. During drilling operations, it is highly beneficial to obtain and analyze formation data such as pressure and temperature.
The availability of reliable formation data is also a benefit after a well enters the production phase. Monitoring formation pressure and temperature, and combining that formation data with measured production and other surface data, enables engineers to better implement an optimal production flowstream designed to maximize recovery from the well. Engineers may also correlate data from adjacent production and injection wells to analyze and predict movement and depletion of reserves produced or flooded by wells completed in the formation of interest.
Existing techniques for testing formations generally include using retrievable formation testing tools. These conventional formation testing tools can be run on wireline or on the drill string for gathering formation data by positioning the formation tester adjacent to the formation of interest in the well and monitoring conditions. Formation conditions in an uncased well may be monitored with wireline formation testing tools such as those described in U.S. Pat. Nos. 3,934,468, 4,860,581, 4,893,505, 4,936,139 and 5,622,223. These methods consume substantial rig time for the removal of the drill string from the well, running the formation testing tool into the wellbore to the formation of interest to acquire formation data, then retrieving the formation tester from the well and, for further drilling or production, the drill string or production tubing must be run into the well. Also, the data available using conventional formation testing tools is available only while the retrievable formation tester is adjacent to the formation of interest.
There are also formation testing tools and methods that are intended for use in cased wellbores such as those described in U.S. Pat. Nos. 5,065,619, 5,195,588 and 5,692,565. A problem inherent for formation testers designed for use in cased wells is that most of these tools involve attempts to patch or plug casing perforations made to afford direct measure of formation fluid pressure.
Like the formation testers run into uncased wells, the formation testers for use in cased wellbores are retrievable and running of the formation tester requires expensive tripping of the drill pipe, and formation data is available only for the time the formation tester is positioned adjacent to the formation of interest.
U.S. patent application Ser. No. 09/293,859, now U.S. Pat. No. 6,234,257 filed on Apr. 16, 1999 and incorporated by reference herein, describes an impact resistant deployable formation data sensing apparatus that may be deployed into a selected formation to provide intermittent or continuous formation data by wireless transmission to data receivers. U.S. application Ser. No. 09/458,764, now abandoned filed on Dec. 10, 1999 and incorporated herein by reference, describes a propellant composition designed for use in such deployment. The present invention also relates to the effective deployment of such data sensing apparatuses into the formation of interest to intermittently or continuously gather and transmit formation data through RF, electromagnetic or telemetric communication to a data receiver. The use of deployable data sensing apparatuses for these purposes is further described in U.S. Pat. Nos. 6,028,534 and 6,070,662, the contents of which are also incorporated herein by reference.
It is an object of the present invention to provide a method and apparatus for deploying a data sensing apparatus into a subsurface geologic formation of interest from a downhole tool to obtain intermittent or continuous monitoring of formation data whether wireline or drill pipe is present in the well bore, thus eliminating or minimizing the need for tripping the well for the sole purpose of running a formation tester.
It is a further object of the present invention to provide a method and apparatus for deploying a data sensing apparatus downhole via either a wireline or a drill string.
It is a further object of the present invention to provide a method and apparatus for deploying a data sensing apparatus into a subsurface geologic formation of interest to obtain intermittent or continuous monitoring of formation data and optimized operation of production or injection from or to the well for optimal depletion of reserves from the monitored formation.
It is a further object of the present invention to provide a durable and reusable structure for deploying data sensing apparatuses into a subsurface geologic formation of interest whereby a high g-force acceleration of a bullet-shaped data sensing apparatus is reliably induced to ensure sufficient penetration and deployment of the data sensing apparatus into the formation rock matrix.
It is a further object of the present invention to provide a data sensing apparatus drill collar propellant gun that can tolerate and operate under high pressures and temperatures encountered in deep wells, and withstand the extremely high pressures and temperatures associated with the use of high energy chemical propellants to propel the data sensing apparatus into a rock formation.
It is a further object of the present invention to provide a data sensing apparatus drill collar propellant gun that is adapted to survive, without deformation, damage, or failure, the high g-forces associated with projectile launch and impact, and the pressures and temperatures resulting from the launch and impact of the data sensing apparatus.
It is a further object of the present invention to provide a method and apparatus for deploying data sensing apparatuses to a satisfactory radial penetration depth into a targeted formation rock matrix to prevent interference with subsequent well operations or damage to the data sensing apparatus during subsequent well operations.
The above-described objects, as well as other objects and advantages, are achieved through the present invention by a method and apparatus for deploying a data sensing apparatus into a targeted geologic formation for gathering data from the subsurface formation.
xe2x80x9cData sensing apparatusxe2x80x9d as used herein preferably includes a shell having a chamber therein and adapted for sustaining forcible propulsion into a subsurface formation, and a data sensor disposed within the chamber of the shell for sensing a formation parameter such as pressure, temperature, resistivity, gamma ray, density, and neutron emissions. Preferably, the shell has a first port therein for communicating properties of a fluid present in the subsurface formation to the data sensor when the apparatus is positioned in the subsurface formation, whereby the data sensor senses at least one of the properties of the fluid. The data sensing apparatus also preferably includes an antenna disposed within the chamber for transmitting signals representative of the fluid property sensed by the data sensor.
xe2x80x9cGun-likexe2x80x9d as used herein includes, but is not limited to, a device for accelerating on object to displace the object from the end of a bore. xe2x80x9cBullet-likexe2x80x9d as used herein includes, but is not limited to, an object shaped with an ogive, conical or pointed cylindrical end or nose. xe2x80x9cNon-alignedxe2x80x9d or xe2x80x9cnot alignedxe2x80x9d means that the axis of the barrel forms an angle, obtuse or acute, with the axis of the burn chamber. Where the burn chamber does not have a readily available axis, xe2x80x9cnon-alignedxe2x80x9d or xe2x80x9cnot alignedxe2x80x9d means that the centroid of the burn chamber does not intersect or coincide with the axis of the barrel.
Real time formation data provides many advantages during both the drilling and the production phases of a well. Real time formation pressure obtained while drilling enables drillers and geologists to predict the formation pressure on a xe2x80x9cmacroxe2x80x9d level and (when provided from a number of distinct sources, such as an array of data sensing apparatuses) enables reservoir engineers to predict drilling fluid and formation pressures on a xe2x80x9cmicroxe2x80x9d level. Using these predictions, drillers and engineers may identify and induce appropriate changes in drilling mud weight and composition to improve drilling rate and promote safety. Using remotely deployed data sensing apparatuses, real time formation data can be obtained and monitored for effective reservoir management without the loss of expensive rig time needed for running conventional formation testers to gather mere xe2x80x9csnapshotsxe2x80x9d of well conditions.
The drill collar propellant gun of the present invention is provided within a section of drill pipe and is adapted for sustaining or imparting forcible propulsion of a data sensing apparatus into a subsurface formation using propellant compositions. The deployment apparatus has a gun-like barrel designed to receive the bullet-like data sensing apparatus and, upon firing, direct the data sensing apparatus into the deployment path. The drill collar propellant gun has a burn chamber adapted to receive the propellant and an ignition assembly designed to induce a reaction in the propellant and thereby generate extremely high pressures and temperatures. The enormous gas expansion caused by ignition and burning of the propellant, when brought to bear on a selected surface of the data sensing apparatus, enables rapid acceleration of the data sensing apparatus along the axis of the barrel and into the side wall of the formation. The ignition of the propellant may be remotely controlled by wired, RF or other electromagnetic or telemetric communication.
The drill collar propellant gun of the present invention preferably includes a barrier, such as a rupture disk, isolating the barrel from the burn chamber. The rupture disk is designed to rupture only when the pressure in the burn chamber reaches a predetermined level. The rupture disk thereby prevents premature movement of the data sensing apparatus along the limited length of the barrel, and provides an overall more efficient launch of the data sensing apparatus for formation penetration.
The drill collar propellant gun preferably also includes a muzzle cap that acts as a sacrificial barrier isolating the interior of the barrel from the drilling mud or other fluid in the wellbore. The muzzle cap is designed to seal the barrel interior from the drilling mud until the muzzle cap is sacrificed upon deployment by the data sensing apparatus. Preferably, the sacrificial barrier shatters into numerous small pieces that can be suspended in and removed by drilling mud in order to prevent interference with data sensing apparatus deployment or continued well functions.
In a preferred embodiment, the barrel is offset from the axial centerline of the drill string and directs a data sensing apparatus fired from the barrel along its radius radially outward from the approximate center of the drillsting into an adjacent rock matrix comprising the formation of interest. In a particularly preferred embodiment, the barrel is not aligned with the burn chamber in order to enable the method and apparatus to be used in a space-limited environment such as in a slender drill string. The projectile fired from the drill collar propellant gun may be similar to the data sensing apparatus described in U.S. patent application Ser. No. 09/019,466, which is incorporated by reference.
The components of the barrel and the burn chamber are adapted for ensuring survival of the drill collar propellant gun without functional failure during deployment of the data sensing apparatus into the formation. The burn chamber of the apparatus is adapted for receiving and igniting, without interference by wellbore fluids, a chemical propellant. The chemical propellant may be stored within the apparatus in the burn chamber itself where it remains until ignition. The propellant must be capable of maintaining its effectiveness without degradation after prolonged exposure to high temperatures and pressures encountered in a well. As mentioned above, the presently preferred propellant for propelling the data sensing apparatus from the drill collar propellant gun is described in U.S. patent application Ser. No. 09/458,764 now abandoned filed on Dec. 10, 1999, which is incorporated herein by reference.
In a preferable embodiment, the drill collar propellant gun has the capacity to deploy multiple data sensing apparatuses at multiple zones of interest throughout the well. Thus, while the present disclosure focuses on the method and apparatus for deployment of a single data sensing apparatus, it should be noted that the drill collar propellant gun may have an array of substantially similar devices, each capable of deploying a data sensing apparatus independently or in concert with the others. The present invention may provide an array of over a dozen substantially similar deployment apparatuses within a single elongated downhole tool in order to prevent having to trip wireline or drill pipe out of the well for each data sensing apparatus deployment.
The drill collar propellant gun of the present invention preferably includes electronic equipment for receiving and interpreting commands for controlled deployment of the data sensing apparatus at a selected depth and orientation. The apparatus may be used in cooperation with one or more positioning systems including, but not limited to, a back up shoe extendable from a side of the drill collar propellant gun and a system for angularly orienting the tool within the wellbore.